I only said “sometimes” because I don’t always have the opportunity to use them. For example, I’d never use them in a proper restaurant. But left to my own devices, hells yeah, a straw. Cold beverages only, though; I’ve never considered having a hot beverage with a straw–wouldn’t it melt?
Anyway, for me, straws are more fun. I don’t care if it’s childish, it gets me to drink more. Also, no lipstick to wash off the glass. (Speaking of vanity: I try not to purse my lips too much–don’t wanna get wrinkles.)
And they’re great when you have a toothache, let me tell you! You can bypass most of your teeth entirely if you put the straw lightly farther back on your tongue. I think this might actually be beneficial for one’s tooth enamel, at least slightly.
Another benefit is mentioned earlier as a joke, but when drinking out of cans or bottles, I definitely will opt for a straw if at all possible. I don’t know where these things have been stored before I got them, or how clean they are. Straws give the illusion (if nothing else) of saving me from the wee little beasties lurking on the unknown can. (I say “illusion” because if they’re lurking on the outside of the can lid, they can probably creep inside once it’s open anyway, so… still, at least I’m not putting my mouth directly on 'em.)
The trick with ice and avoiding the “drinking the warmest part of the drink,” RealityChuck, is lifting the straw a bit and sipping so the end is in the ice section. Easy.
Finally, with milkshakes, ideally it’s thick enough to enjoy with a spoon. If not, definitely a straw for me. It feels like it lasts longer that way, too.
P.S. All the better if it’s a bendy straw! Loooove bendy straws. Just the little plasticky noise they make when bending them back and forth makes me nostalgic and happy. Silly I know.